Benefits of the "Convention over Configuration" paradigm

Convention states that 90% of the time it will be a certain way. When you deviate from that convention then you can make changes...versus forcing each and every user to understand each and every configuration parameter. The idea is that if you need it to differ you will search it out at that point in time versus trying to wrap your head around all the configuration parameters when it often times has no real value.

IMHO it always makes sense. Making convention the priority over explicit configuration is ideal. Again if someone has a concern, they will force themselves to investigate the need.

I think the benefit is simple: No configuration necessary. You don't need to define locations for this-or-that type of resource, for example, for the app/framework to find them itself.

As for cases where it does not make sense: any situation where it will be fairly frequent that alternative configurations would be required, or where it makes sense that a developer/admin would need to 'opt-in' to some behavior explicitly (for example, to prevent unintended and unexpected side-effects that could have security implications).

The benefit of convention over configuration paradigm in web development the productivity since you won't be required to configured to set all the rules and there are less decision that a programmer has to make. This is evident when using the .NET Framework.